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Biomedical subjects

C R Magnussen

Publications and source records attributed to C R Magnussen.

32 records · Page 2Linked to original sources

Aberrant forms of Escherichia coli in blood cultures: in vitro reproduction of an in vivo observation.

Aberrant filamentous forms of Escherichia coli were observed on direct Gram stain of blood cultures from a patient being treated with the beta-lactam antibiotic cephalexin. After the institution of an alternative antibiotic regimen which included a different cell wall-active agent, E. coli of normal morphology was detected in blood cultures for an additional 48 h. Filamentous forms of E. coli could be reproduced reliably in vitro by incubating the organism in Mueller-Hinton broth containing various concentrations of cephalexin. Both supra- and subinhibitory concentrations of cephalexin resulted in filament formation after 4 h of incubation, whereas 24 h of incubation yielded intact filaments at only a narrow range of subinhibitory concentrations of cephalexin. In vitro comparison of the ability of cephalexin, cephalothin, ampicillin, and gentamicin to cause filamentous forms of E. coli showed that cephalexin and cephalothin produced pure filament formation after 4 h of incubation at subinhibitory concentrations of as low as one-fourth the minimum inhibitory concentration of the antibiotic. Ampicillin was not associated with pure filament formation at concentrations below the minimum inhibitory concentration, and gentamicin produced no filaments at any concentration. The effect of preincubation of E. coli with subinhibitory concentrations of cephalexin on subsequent minimum inhibitory concentrations of ampicillin was examined in an effort to develop an explanation for the persistent sepsis exhibited by the patient. No diminution of the activity of ampicillin by preincubation with cephalexin could be demonstrated. Other possible clinical implications of filamentous forms of gram-negative bacilli are discussed.

Ampicillin↗

Haemophilus influenzae tenosynovitis.

A case is reported of polytenosynovitis in a 31-year-old male during the course of a severe bacteraemic illness caused by Haemophilus influenzae type b. The clinical presentation was similar to tenosynovitis caused by bacterial or viral agents. As the management of the H. influenzae tenosynovitis would differ from that due to other causes, the addition of H. influenzae type b to a differential of tenosynovitis should be considered. Recognition and prompt treatment by appropriate antibiotics may be important to avoid suppurative complications affecting the tendons. As the pathophysiology of the tenosynovitis is not clear, careful bacteriological and immunological assessment must be obtained.

Adult↗

Herpes simplex virus and recurrent laryngeal nerve paralysis. Report of a case and review of the literature.

A 61-year-old man experienced the abrupt onset of a nonspecific febrile illness followed by the acute development of bilateral vocal cord paralysis. There was no evidence for Guillain-Barré syndrome, multiple sclerosis, brainstem encephalitis, myasthenia gravis, metabolic encephalopathy, poliomyelitis, diphtheria, botulism, tumor, vasculitis, or extrinsic nerve compression. No cause for the fever was ascertained, and the vocal cord paralysis improved sponaneously. Acute and convalescent viral serological studies demonstrated a diagnostic complement-fixation antibody titer rise to herpes simplex virus (HSV) and no rise in titer to influenza A and B, cytomegalovirus, poliomyelitis, or Mycoplasma. This case is similar to several others reported in the literature that suggest a viral neuritis in tenth nerve paralyses in children. The difficulties involved in diagnosing HSV CNS disease before death are discussed, and the medical literature is reviewed for evidence that HSV is the etiological agent in selected cranial neuropathies.

Antibodies, Viral↗

Candida fungus balls in the common bile duct. Unusual manifestation of disseminated candidiasis.

Disseminated candidiasis appearing as Candida fungus balls in the common bile duct developed in a patient with acute myelogenous leukemia. The patient had received broad-spectrum antimicrobial therapy for fever of unclear origin and subsequently manifested signs of liver cell dysfunction. A percutaneous transhepatic cholangiogram demonstrated three radiolucent defects in the distal part of the common bile duct, which proved to be fungus balls at operation. The liver was studded with microabscesses that disclosed C albicans on biopsy. The biliary tract fungus balls were removed surgically, and the patient was treated with 2,001 mg of intravenously administered amphotericin B over a 2 1/2-month period. No evidence of Candida infection is evident eight months after completion of therapy.

Acute Disease↗

Double-blind evaluation of oral ribavirin (Virazole) in experimental influenza A virus infection in volunteers.

The prophylactic effectiveness of oral administration of ribavirin (1-beta-d-ribofuranosyl-1,2,4-triazole-3-carboxamide) against experimentally induced influenza A infection was evaluated in a double-blind clinical trial in normal volunteers. Fourteen men received ribavirin capsules (1,000 mg/day in four divided doses) and 15 other men received identical-appearing placebo capsules beginning 6 h after the intranasal inoculation of 3.4 log(10) 50% tissue culture infectious doses of influenza virus A/Victoria/3/75 H3N2 and continuing for 5 days after challenge. The total number of moderate-to-severe symptom scores and the total number of temperatures >/=100 degrees F (37.8 degrees C) were significantly lower in the ribavirin group compared with the placebo group. The mean quantity of virus shed in nasal wash specimens and the total number of days that there were viral titers greater than 1.0 log(10) 50% tissue culture infectious doses per ml were significantly greater in the placebo group. There was no difference between the frequencies of virus isolated or the antibody responses in the two groups. Therefore, prophylactic ribavirin ameliorated symptoms and fever indicative of moderate-to-severe illness, but had no effect on the manifestations of mild illness in response to influenza A challenge. A transient rise in total serum bilirubin occurred in 29% of the ribavirin-treated volunteers and in none of the placebo-treated volunteers.

Adult↗

Comparative effects of glycerol and dextrose on porphyrin precursor excretion in acute intermittent porphyria.

The effects of dietary manipulations on excretion of the porphyrin precursors, delta-aminolevulinic acid (ALA), and porphobilinogen (PBG) were studied in eight patients with acute intermittent porphyria. Three diet periods of 9-17 days comprised each study. In each patient, a "baseline" protein, fat, and carbohydrate intake was kept constant throughout. In addition, during the first diet period each patient received 150 g dextrose; during the second, this was replaced by an isocaloric amount of neutral fat; and during the third, the fat was replaced by 150 g glycerol. In each of the patients, three comparisons of the effect of diet on both ALA and PBG excretion were made: (1) 300 g carbohydrate versus 150 g carbohydrate (dextrose versus fat), (2) 150 g carbohydrate + 150 g glycerol versus 150 g carbohydrate (glycerol versus fat), and (3) 300 g carbohydrate versus 150 g carbohydrate + 150 g glycerol (dextrose versus glycerol). For each of these three diet comparisons, there are sixteen individual comparisons possible for the effect of diet on porphyrin precursor excretion, eight for ALA and eight for PBG. Thus, the mean values for ALA and PBG excretions during each of the diet periods are statistically compared internally within each individual patient. Increasing carbohydrate intake from 150 g to 300 g by isocaloric substitution of dextrose for fat produced a significant (p less than 0.05) decline in eight of the sixteen comparisons of ALA and PBG excretion. Addition of 150 g glycerol by isocaloric substitution for fat caused a significant (p less than 0.05) decline in nine of the sixteen possible comparisons. In the sixteen comparisons of isocaloric dextrose and isocaloric glycerol-substituted diets, dextrose produced significantly (p less than 0.05) lower porphyrin precursor excretion in four cases and glycerol produced significantly (p less than 0.05) lower values in five. One patient showed no significant change on any of the diets. Of the four patients having symptoms believed referrable to porphyria during the study, three reported an improvement in symptoms during the high glycerol intake. The effects of dietary perturbations on porphyrin precursor excretion in acute intermittent porphyria are variable, but glycerol appears to be capable of decreasing the excretions and may prove useful in treating some of these patients.

Acute Disease↗

Exacerbation of porphyria during treatment of pulmonary tuberculosis.

Several attacks of acute intermittent porphyria complicated the treatment of a patient with pulmonary tuberculosis. To determine whether the attacks were drug-induced, the ability of a variety of antituberculous drugs to induce (delta)-amino-levulinic acid synthetase activity in a rat liver model was assessed. Pyrazinamide was found to be capable of significantly inducing amino-levulinic acid synthetase activity; the other antituberculous drugs caused either slight or no induction of amino-levulinic acid synthetase. The data suggest that pyrazinamide was capable of causing an exacerbation of the patient's porphyria. Tuberculosis, by causing debility, may also have aggravated this patient's previously latent porphyria.

5-Aminolevulinate Synthetase↗

Grand mal seizures and acute intermittent porphyria. The problem of differential diagnosis and treatment.

A 36-year-old white man had both acute intermittent porphyria and long-standing idiopathic grand mal seizures. Diphenylhydantoin apparently adversely affected both the clinical and biochemical parameters of the acute intermittent porphyria. Comparison of urinary levels of the porphyrin precursors, delta aminolevulinic acid and porphobilinogen, under controlled diet conditions before and after withdrawal of diphenylhydantoin, showed that this drug accounted for approximately one-half of the porphyrin precursor excretion. Significant clinical improvement of the porphyria followed withdrawal of the diphenylhydantoin. Bromides appeared to be approximately as effective as diphenylhydantoin for seizure control in this patient.

5-Aminolevulinate Synthetase↗

Acute intermittent porphyria: clinical and selected research aspects.

Acute intermittent porphyria is an inborn error of metabolism characterized by the excretion of excess porphyrin precursors (porphobilinogen and usually delta-aminolevulinic acid) in the urine, and by sporadic attacks of neurologic dysfunction. The disease is complex, involving variable patterns of autonomic and peripheral neuropathy as well as the central nervous system manifestations. There may be alterations in carbohydrate, lipid, water, and electrolyte metabolism in addition to clinically inapparent endocrine abnormalities. The fundamental defect is thought to be a 50% decrease of uroporphyrinogen I synthetase, the third enzyme of the heme biosynthetic pathway. This is associated with a marked increase of hepatic delta-aminolevulinic acid synthetase, the first and rate controlling enzyme of the pathway. The measurement of uroporphyrinogen I synthetase in erythrocytes now provides an enzyme diagnostic test for the disease. Two therapeutic approaches that may prove to reverse the fundamental disease process, at least in some patients, involve [1] a high carbohydrate intake, and [2] intravenous administration of hematin. The latter, only recently introduced, is now being investigated.

Acute Disease↗

Gentamicin and tobramycin resistant gram-negative bacilli in a community hospital.

The incidence and spectrum of resistance to gentamicin and tobramycin among gram-negative bacilli (GNB) isolated in a community hospital over a one-year period were studied. The overall incidence of resistance was 3.7%. Pseudomonads constituted almost half of the resistant organisms. The majority of resistant GNB was isolated from the respiratory and urinary tracts. Acquisition of resistance was correlated with both the total use of gentamicin in the hospital and recent treatment of individual patients with gentamicin plus tobramycin. The overall incidence of resistant isolates (3.7%) and the incidence of resistance for the enterobacteriaceae (1.9%) were lower than rates reported by comparable studies at several university or municipal hospitals.

Aged↗

Legionnaires' lung abscess.

A patient with a clinical course consistent with Legionnaires' disease rapidly developed acute respiratory failure. Sputa and bronchoscopic washings revealed many polymorphonuclear leukocytes but no organisms on gram stain and culture. The diagnosis of Legionnaires' disease was strengthened when the transthoracic aspirate revealed weakly staining gram-negative bacilli with no growth noted on culture. Serologic titers confirmed the diagnosis of Legionnaires' disease. This patient's course was complicated by cavitation which responded to medical therapy with erythromycin. This is the second reported case of Legionnaires' lung abscess.

Adult↗